fn printer_error(s: &str) -> String {
    let n = s.chars().filter(|c| *c < 'a' || *c > 'm').count();
    format!("{}/{}", n, s.len())
}

//#[test]
fn should_pass_all_the_tests_provided() {
    assert_eq!(
        &printer_error("aaaaaaaaaaaaaaaabbbbbbbbbbbbbbbbbbmmmmmmmmmmmmmmmmmmmxyz"),
        "3/56"
    );
    assert_eq!(
        &printer_error("kkkwwwaaaaaaaaaaaaaabbbbbbbbbbbbbbbbbbmmmmmmmmmmmmmmmmmmmxyz"),
        "6/60"
    );
    assert_eq!(
        &printer_error("kkkwwwaaaaaaaaaaaaaabbbbbbbbbbbbbbbbbbmmmmmmmmmmmmmmmmmmmxyzuuuuu"),
        "11/65"
    );
}
